1. Field of the Invention
The present invention relates to biodegradable materials. In particular, the present invention relates to biodegradable materials that return to their original shapes even after being stretched by a relatively significant amount.
2. Discussion of the Related Art
There has been great interest in the use of biodegradable materials for tissue regeneration use. One proposed application, for example, is the use of biodegradable arterial and venal vascular grafts. The biodegradable vascular graft would replace or bypass a damaged native blood vessel until the body's tissue regeneration mechanism regenerates new vascular tissue to replace the degrading vascular graft. To be successful, the vascular graft needs to be compatible and, preferably, promote cell attachment and provide a habitable environment for the growing new tissue. In addition, because the pressure in the circulatory system changes between the systolic pressure and the diastolic pressure within each heartbeat, the vascular graft is preferable flexible, i.e., without permanent deformation as a result of the higher systolic pressure.
Another proposed application for biodegradable materials, for example, is to provide support for an implanted prosthetic tissue or device, such as a breast implant or a pacemaker. An artificial prosthetic tissue made of biodegradable material would provide support to the implanted prosthetic tissue or device until the body's tissue regeneration mechanism replaces the degrading artificial prosthetic tissue with new connective tissue. Until then, the artificial prosthetic tissue needs to be flexible to avoid permanent deformation due to forces resulting from the patient's normal activities, such as normal ambulatory activities and exercise. For that application, the prosthetic tissue preferably should promote cell attachment and cell growth necessary for regeneration of the native connective tissue.
Therefore, a biodegradable material with shape-retention abilities (“shape memory”) and which promotes cell attachment and growth is desired.